Christians in Nigeria say their government isn't doing enough to protect them from militant Muslims. Thousands of Christians have been killed in recent attacks -- especially in northern and central Nigeria.

Several human rights groups have called on America and the United Nations to intervene.

One of the worst attacks in recent years occurred March 7. Unlike many previous raids on Christian villages, militant Muslims attacked the village of Dogo Nashawa late at night, instead of during the day.

"When you attack people who are sleeping, innocent people who are unprepared, that's a massacre," said Emmanuel Ogebe of Advocates International.

Many villagers were hacked to death or burned alive in their houses and children as young as five years of age were among the 500 Christians that were murdered.

There was another first -- many of those who survived said the militants leading the attack were firing AK-47 assault rifles.

"It's a whole new level, completely that we haven't seen before," Ogebe said. "They are nomads whose weapon of choice is machetes and bows and arrows. So, we want to understand how they got this sophisticated weapons."

The Nigerian government promised to investigate, punish the perpetrators and act to help prevent future incidents.

Despite those assurances, there was another attack against a Christian village last October. Again, in the middle of the night, automatic weapons were used.

Mark Lipdo arrived on the scene shortly after the raid.

"I got there about 4 a.m. and 3:02 what we saw were six people massacred," Lipdo said. "In a pool of their blood and houses were set ablaze. About 21 houses were burnt down and then there were gunshots, like holes of bullets through the doors."

Lipdo said he talked to many survivors -- including a man who explained what happened to his family.

"His house was set ablaze as his family was trying to escape," Lipdo added. "His wife was killed in the presence of his children. And of his three of his children, one little one was about five-years-old, was burned alive trying to escape."

Most of the recent attacks have occurred in central Nigeria -- in the Plateau state. Twelve of Nigeria's northern states are ruled by Shariah or Islamic law.

Dr. David Carling is a missionary to Nigeria. He said Plateau state is a key battleground.

"It's standing in the way of this jihadic desire to bring Islam into the whole country," Carling said. "So, they are unleashing everything and it's linked-unfortunately it's link with outside agencies and forces."

Carling first came to Nigeria in 1958, serving as a medical missionary. He suggested Islamists have become more violent and agressive in recent years, because Nigeria is crucial to their plans to spread Islam throughout Africa.

"Everything has been unleashed in a horrendous way in Nigeria," Carling said. "It is actually a strategic nation, no doubt about that."

"No one has been tried and prosecuted for any of the thousands, literally thousands of deaths that have occurred in Nigeria in all of the years that we've had this sort of crisis," Ogebe said. "Our objective is to end the impunity. There has to be a point when we say no, enough is enough, we are not going to have this anymore in this country. There must be consequences for taking the lives of people."

What should Christians around the world do?

"We can pray, we can support, we can understand and obviously there are huge responses needed financially as well but that's something that the Lord needs to lay on people's hearts," Carling said.

Mark Lipdo agreed with Carling, but he believes an important mission for his Stefanos Foundation is to bring forgiveness.

"Our aim is to enable the Christians in Nigeria to learn to say we have forgiven the perpetrators," Lipdo said. "If we don't do that, then we are cheated twice. Because apart from the hurts, apart from the killings, and the lives that are lost and properties that are lost we also lose the values, the core value of Christianity which is love."